Along with thick rough, tight lies, undulating greens and deep pot bunkers, a major line of defence for links courses is the weather, which can often create a big advantage for one side of the draw.
More than a couple of Open Championships have been disrupted by the seaside weather, and since there's around 156 players using a one-tee start the first two rounds go on all day.
Padraig Harrington will hit the opening tee shot at 6.35am on Thursday morning, with the final group not getting under way until 4.10pm - and that means conditions can change dramatically for early and late starters.
And if weather rolls in later on Thursday and hangs around for Friday morning there can be a big advantage for those who go out early Thursday and late Friday - or vice versa of course.
But what do conditions look like at Royal Portrush and does anyone hold an advantage?
So the tee times really do matter at The Open, definitely more so than at any other Major, and although it looks relatively even this week the advantage does look to be for those going out early Thursday.
As there is a warning for thunderstorms at Royal Portrush on Thursday, which officially starts at around 11:00am but with chances increasing as the day goes on.
The rain certainly gets heavier as the day goes on, as crucially does the wind which is always a huge factour out on the links.
And on Friday, although more rain is again forecast in the afternoon than the morning, the change isn't as great so there's less of an advantage going out early in the second round.
There's also the possibility of some disruption to play later on Thursday which could result in some late finishes - and again would give early first round starters the edge.
So if you're trying to pick a winner it's worth consulting the tee times as those with an early start Thursday and later round on Friday could well escape the worst of conditions - and any extra edge you can get in an Open Championship helps.
Weather forecast for the Open Championship
The official weather update bulletin from the Open Championship for Thursday and Friday is as follows:
Round One Thursday: Cloudy and dry but some short-lived outbreaks of rain, perhaps briefly heavy at times, are possible. Intermittently dry through the afternoon and evening but there is a chance of further rain and heavy showers or passing thunderstorms developing. High: 22°C (72°F).
Round Two Friday: A drier and brighter morning likely. Some showers may develop through the afternoon. Again, these could possibly be heavy and with a small chance of thunder. Winds changeable with gusts of up to 12 mph. High: 21°C (70°F).
